Disrupted communication between the gut and brain causes the signs and symptoms of irritable bowel syndrome (IBS). This type of condition is a functional gastrointestinal disorder.

Research is still ongoing into exactly why some people get IBS. It may be that their gut is especially sensitive to stress or certain foods.

Around 12 percent of adults in the United States have IBS. Women are twice as likely to have IBS than men. It is also more common in people under the age of 50.

This article explores 10 symptoms of IBS. Read on to learn how to recognize it. We also discuss other conditions that could cause similar symptoms.

1. Pain and cramps

Experiencing pain and cramps in the lower abdomen are two of the main symptoms of IBS.

An oversensitivity of the gut likely causes these symptoms.

IBS affects how the brain and gut work together, and the condition may cause the muscles in the gut to contract more than they need to for a normal bowel movement.

Excessive gut muscle contractions may lead to lower abdominal pain and cramping.

2. Excessive gas

People with IBS may experience excessive gas. Doctors do not know the exact reason for this, though there are several theories.

One theory is that IBS causes a problem with bacteria in the gut. Bacteria can create certain toxins that may cause excessive gas.

Another theory is that the guts of people with IBS are less able to tolerate and transport gas. This leads to people with IBS feeling more gassy than other people.

3. Bloating

Feeling bloated is another symptom of IBS. Bloating refers to a collection of gas in the gut, which can cause the abdomen to feel full and appear rounder than usual. The same factors that cause excessive gas in IBS may also cause bloating.

4. Diarrhea

Diarrhea is a key symptom of IBS. It happens because the muscles in the gut contract more than they need to. Diarrhea may be accompanied by a feeling of muscle cramps.

To produce a normal bowel movement, the gut contracts and relaxes in a rhythmic way. In IBS, however, this rhythm is disrupted. IBS can either speed up or slow down gut muscle contractions. So, IBS can cause both constipation and diarrhea at different times.

As with other IBS symptoms, diarrhea is related to how the brain and gut communicate. Research into exactly why this happens is ongoing.

5. Constipation

Constipation occurs when a person finds it difficult to pass stool. A person has constipation when they have:

• fewer than three bowel movements in a week
• hard, dry, or lumpy stools
• difficulty or pain when passing stool
• a feeling of an incomplete bowel movement

There are many possible causes of constipation, including dehydration, a lack of fiber in the diet, and stress. IBS can also cause constipation by affecting how the muscles in the gut contract.

When someone is constipated, their gut muscles do not contract as much as they should.

Depending on a person’s specific symptoms, a doctor may refer to the following types of IBS:

• IBS with diarrhea, which is diarrhea and only occasional constipation
• IBS with constipation, which is constipation and only occasional diarrhea
• IBS with mixed bowel habits, which is when a person regularly has both constipation and diarrhea

Doctors may also refer to constipation-predominant and diarrhea-predominant IBS.

6. Sensitivity to fermentable oligo-, di-, mono-saccharides and polyols

People with IBS may be more sensitive to fermentable oligo-, di-, mono-saccharides and polyols (FODMAP) foods. These are types of carbohydrate that can cause inflammation or irritation in the gut.

FODMAPs can increase the amount of water going into the gut, and bacteria in the gut may cause them to ferment. This can increase intestinal gas.

People may be able to reduce the symptoms of IBS by avoiding high-FODMAP foods, which include:

• onions
• avocados
• lentils
• garlic
• beans
• almonds
• cashews

For many people with IBS, eating FODMAPs triggers other IBS signs and symptoms. A 2017 meta-analysis found that consuming a low-FODMAP diet may improve symptoms of IBS.

Learn more about the link between FODMAP diets and IBS here.

7. Fatigue

Feeling very tired or fatigued is another common symptom of IBS.

One review found that fatigue occurred alongside other IBS symptoms, including bowel-related symptoms, psychological distress, and health-related quality of life.

More research is needed, as medical professionals still do not fully understand why IBS sometimes leads to fatigue.

8. Joint pain

People with IBS may be more likely to experience joint pain. Scientists still do not know why, but it may be due to increased inflammation in the body.

A 2017 study found that people with IBS had an increased risk of a type of joint pain called temporomandibular disorder. More research is needed to understand this link, however.

9. Feeling stressed

There is a strong link between IBS and stress. The nervous system controls the gut as well as responds to psychological stress.

The link between IBS and stress goes both ways. Feeling stressed can worsen IBS symptoms, and the physical symptoms of IBS can cause psychological distress.

10. Brain fog

Intestinal gas and bloating, which are symptoms of IBS, are also linked with brain fog.

Brain fog, or foggy thinking, describes mental confusion, impaired judgement, and trouble concentrating.

More research is needed to fully understand the link between problems with the gut and brain fog, however.

What else could it be?

IBS is not the only explanation for the symptoms explored in this article. It is best to speak to a doctor to get a proper diagnosis.

Experiencing excessive gas or bloating does not necessarily mean that a person has IBS. If they start to become gassy soon after eating, they may have small intestinal bacterial overgrowth.

Also, getting diarrhea frequently or urgently may be a sign of:

• inflammatory bowel disease
• celiac disease
• bile acid malabsorption
• dumping syndrome

Outlook

IBS is a long-term health condition that can affect a person’s well-being if they do not seek treatment. Understanding the signs and symptoms of IBS can help a person experiencing the condition to get appropriate help.

Many treatment options are available to help a person with IBS manage their condition. Many of these focus on the link between stress and IBS. A doctor may also recommend counseling and progressive relaxation techniques as a way to ease symptoms.